Building Up A Vintage Ford Six-Cylinder Engine

Six-cylinder engines don't get much respect in performance circles. After all, they're buzzy, down on power, and they tend to remind us of Saturday morning at the grocery store with mom when we were young. But make no mistake, Ford's old, reliable in-line

Jim Smart

September 1, 1999

Think back to that Saturday night long ago when you and your buddies took an old Falcon out for a joyride, putting the little Ford six through unequaled hell, thinking it would blow up before the night was over. The humble Ford six-popper outlasted you that night. It was still running the next morning when you woke up with that awful hangover. What's more, it propelled you to the drugstore for relief. Remember? Thirty-five years ago, in-line sixes were burning up dragstrips in budget racers from coast to coast. The dated in-line six contributes something important to acceleration--low-end torque, which owns the holeshot so important to traffic-light and Christmas-tree challenges. Getting there quickly boils down to how much torque your engine makes when the throttle's opened.

Back in the '60s, budget drag racers knew how to get an in-line six to perform. They did it with induction, raising the compression, improving the ignition, and helping the engine scavenge exhaust gas effectively. These old-timey performance tips are still very much in style today. Jay Crouch of Clifford Performance walks with the throaty buzz of an in-line six in his stride. So does Clifford Performance, which has been achieving in-line excellence since the '60s. For those of you with six-cylinder Mustangs and Falcons thinking about a V-8 engine swap, you may want to think again before going to the expense and trouble. Clifford Performance has fast answers for the 144, 170, 200, and 250ci sixes originally installed in the Falcon, Comet, Fairlane, Mustang, Maverick, Fairmont, Zephyr, and even the Econoline van. When Ford introduced the light-weight, graywall iron six in the '60 Falcon, it was a mild player sporting 144 ci stacked above four main bearings. The 144 grew to 170 ci, then 200, and ultimately 250. Ford achieved the additional displacement via bore and stroke enlargement.

What makes the 200 and 250ci sixes more appealing for performance is the seven main bearing design, first introduced in 1962, as opposed to the four main bearings in the 144 and 170ci sixes. Seven main bearings make the 200/250ci structurally sound for high-rev spins. Crouch tells us you can rev the 200ci six reliably to 7,000 rpm. Stick that one in your 289-2V and smoke it. Seven main bearings make the 200/250ci sixes solid performers because that's a lot of support across the crankshaft--at least one main bearing per cylinder. It's a greater level of support than you'll find in any V-8 engine, which typically has five main bearings. You will likely never ring your Ford six to 7,000 rpm, but this tells us just how capable this engine is. We're going to focus mostly on street performance from the 144/170/200/250ci sixes because that's what most of you with sixes are seeking. If you're toying with a '60-'65 Falcon, Comet, or Mustang with the 144 or 170ci six, much of what we're about to say about the 200ci six also applies to your application. Aside from the seven main bearing design, the 200ci six is virtually identical to the 144 and 170ci sixes. If you're not concerned about originality, you will want to step up to a 200ci six for your six-cylinder compact because it's just common sense. By the same token, the 250ci six sports its own share of challenges, which makes the baby-brother 200 more ideal for performance.

Build a Better Six Crouch, a seasoned engine builder familiar with the Ford six, suggests overkill when you're building a 200ci six. He recommends the 200 for the most obvious reasons--displacement and seven main bearing support. He discourages building a 250 if your goal is purely cubic inches. The 250's taller deck and longer stroke are a disadvantage because they limit revs. Risk of engine failure becomes higher with the 250. Crouch is convinced he'll get arguments on this one, but he believes in the 200 based on years of experience. Crouch suggests asking yourself what the engine's mission will be. Street sixes need a healthy bottom end, in fact, a bottom end that could actually stand up to racing conditions if necessary. He suggests overkill on a street engine for longevity--200,000 miles or more before the next rebuild, plus a mill that will make power with less chance of failure. He achieves this using the best parts down under--forged pistons, Clevite bearings, beefed-up connecting rods and crankshaft, and the best machining techniques.

Crouch says to build a 200 six just like you would a V-8. Hot tank the block, then media blast for improved aesthetics. Then Magnaflux to inspect for cracks. Machining begins with boring and honing using a torque plate, which bolts to the block and is torqued just like a cylinder head to "pull" the cylinder bores into the shape they will be with the head installed. Align honing the main bearing caps and saddles gets the block true. Milling the deck of not only the block, but also the head, perfects the mating surfaces. Try this with the exhaust manifold mating surfaces while you're at it. Crouch suggests maximum recon-ditioning of the connecting rods--Magnafluxed, shotpeened, heat treated, and fitted with ARP rod bolts for strength. He adds that you have the option of press-fit or full-floating piston pins, which afford the piston more freedom of movement on the rod. Moly piston rings yield a better break-in because they seat more quickly. Machining, deburring, and nitriding the crankshaft is also recommended for strength.

Balancing an in-line six is critical to smoothness at high revs. Reciprocating mass, namely pistons and rods, must be balanced with the crankshaft counterweights for smoothness. Not only is vibration annoying, it's destructive. We suggest dynamic balancing everything that spins, including the pulleys, for unending smoothness. Infuse power into the 200 six with improved breathing, just like a V-8. For Clifford Performance, this means porting and polishing the head, with the installation of larger 1.74-inch (intake) and 1.50-inch (exhaust) Chevrolet valves. This is an easy modification performed during a valve job. When we asked Crouch about the even larger 1.88-inch intake valve, he told us breathing was only marginally improved, with a loss in low-end torque.

For exhaust headers, Crouch suggests keeping an ear on noise levels. Few things are more offensive than a loud six-cylinder exhaust system. Dual exhaust headers tied to three-chamber Flowmasters or even stock dual exhausts are recommended. These mufflers will give your six a mellow exhaust burble at the trumpets, plus they will protect you from hearing loss. Six-cylinder induction systems are always a point of debate. Clifford covers all the bases with multi- and single-carb setups for Ford sixes. Most popular from a visual (and performance) standpoint is the Tri-Power setup--three one-barrel Weber carbs atop an Offenhauser aluminum intake. The Offy setup was originally designed for Autolite 1100 and Holley single-throat carbs. Clifford offers the reliable Weber with years of proven performance. This is a nice-looking induction package available with Clifford-exclusive K&N air filters. The Tri-Power setup runs on a single carburetor until you hit the gas, which brings in the other pair.

Clifford offers single-carburetor performance with a duo of two-barrel carburetors for Ford sixes. The Weber 5200 two-barrel is one option where less carburetion is needed. What you can expect from the Weber two-barrel is improved torque in the low- and mid-ranges, while the larger Holley 2300 series two-barrel in 280-, 350-, 500-, and 650-cfm sizes is more appropriate for high-revving sixes that need to make torque on the high end. Don't kid yourself into believing your 200 street six needs a 650-cfm carb. You'll suffocate the darned thing in air and fuel. At best, a warmed-up street six can handle 350 cfm at best, and that's pushing the envelope. Two types of adapters are available for the Holley, and one for the Weber, to enable you to bolt these carbs onto a stock manifold.

What About the BIG Sixes?

Though very few of you will have an interest in the 200-six's biggest brothers, the 240 and 300ci sixes, we're going to share some information with you. The 240 and 300ci sixes were installed in large cars, trucks, and vans from the '60s until the '90s. In fact, the 300ci six was equipped with port fuel injection until its demise two years ago. Clifford Performance offers a lot for the big Ford sixes. Crouch tells us the 300ci makes more torque, and has a broader torque curve, than the 302ci V-8. The 300ci six has a 4-inch bore with a 3.96-inch stroke. Put these numbers alongside the 302 V-8 (4-inch bore with a 3.00-inch stroke) and we find the 300 six has the clear advantage. Serious huffage (and leverage!) going on here. Plus, if built, ignited, and aspirated properly, it will take a 7,000-rpm blast.

If you have a passion for Ford sixes and want to spank your buddies at the traffic light, consider the installation of a 300 six in your Mustang or Falcon. Why? With special engine mounts, Clifford makes it possible to drop a 240 or 300ci six into your Ford compact with hood clearance to spare. So what's available for the 240/300ci six from Clifford? Plenty! Five differ- ent manifolds--two fours, three twos, one four, one two, and two twos. Cast-aluminum valve covers. Custom-forged pistons. Mallory ignition. High-performance oil and water pumps. Even forged crankshafts. Ultimately, you can achieve 600 hp and 7,000 rpm with a 300ci Ford six. Just imagine the possibilities in your sleeper street car.